Biltong Box rod holders. Bunnings in Australia sells 6.3mm galvanised rods in 1m lengths, I preferred to use them over wooden ones. 

I printed them in TPU so they have a bit of flex, drill holes in the plastic crate and insert them. You can then cut the rods to length and insert them into the rod holders.

I bought the computer fan an filters from Amazon.

PS Biltong is similar to jerky but better ;)